The invention relates to an internally ventilated brake disc having at least two friction rings, which are held apart from each other by ribs, and including air blades, which are fastened to the brake disc and which extend essentially from the inner circumference of a friction ring in the radial direction by a defined amount in the direction of the axis of rotation of the brake disc, in order to deliver a cooling air flow through the space between the friction rings, when the brake disc is rotating. With respect to the prior art, reference is made not only to DE-OS 15 55 186 and DE 196 52 464 A1, but also to DE 10 2008 016 037 A1.
An effective cooling of brake discs, which are installed, for example, in motor vehicles, can be very important. For this reason, attempts known to the person skilled in the art have been made to deliver an adequate (cooling) air flow, which is drawn in from the surroundings, into the space between the internally ventilated brake discs. In simpler cases the ribs, which are provided between the (two) friction rings of an internally ventilated brake disc, bring about this transport of the air flow. In this respect it is known to provide a protective cover, which is provided apart from or, more specifically, on one side of the brake disc, with suitable air conducting devices that are supposed to guarantee an adequate cooling air flow. Whereas the air conducting devices in these known protective covers do not move relative to the vehicle even when the brake disc is rotating, there also exist brake discs with air conducting blades or air blades that are fastened to the brake discs. When the brake disc rotates, these air blades move, naturally together with the brake disc, relative to the vehicle, that is, they rotate about the rotational axis of the brake disc. Of course, such rotating air blades can deliver a cooling air flow in an especially effective way and, if suitably configured, in particular, also into the space between the two friction rings of an internally ventilated brake disc.
DE 10 2008 016 037 A1, mentioned above, shows a brake disc with air blades, which are arranged on the brake disc in this way. These air blades are formed by suitably elongated ribs that extend, when viewed in the radial direction, beyond the friction rings over a defined distance in the direction of the rotational axis of the brake disc and, in so doing, are suitably formed. For example, these ribs can be inclined relative to the surface of the friction ring and, as a result, are aligned relative to this surface so as not to be perpendicular; or the continuations of the ribs that extend beyond the friction rings can extend in a suitably curved manner.
However, the casting process for manufacturing such specially formed ribs and, therefore, the casting process for manufacturing such a brake disc in its entirety is relatively time-consuming and costly.
There is therefore needed a brake disc that is simplified in comparison to the prior art.
This and other needs are met by an internally ventilated brake disc comprising at least two friction rings, which are held apart from each other by ribs, and comprising air blades, which are fastened to the brake disc and which extend essentially from the inner circumference of a friction ring in the radial direction by a defined amount in the direction of the axis of rotation of the brake disc, in order to deliver a cooling air flow through the space between the friction rings when the brake disc is rotating. The air blades are formed by a sheet metal part, or a plurality of sheet metal parts, that is or are connected to at least some of the ribs.
If the air blades are formed, as proposed, by an initially independent sheet metal part, then the manufacture of especially complex and formed air blades is significantly simplified over the closest prior art. Such an approach simplifies the manufacture of even complex shapes that in terms of function are designed, or rather can be designed, in the best possible way, that is, to deliver an air flow. Even though it is possible for each individual air blade to be formed by an independent sheet metal part, it is simpler from a manufacturing view point, especially with respect to the fastening of the air blades to the brake disc, to combine a plurality of air blades to form one sheet metal part. This fastening can best be done on the ribs between the friction rings without impairing the friction rings. At the same time not every one of these ribs has to be used explicitly to fasten the air blade sheet metal part(s). Rather, it may be adequate enough to provide a fastening on just some ribs, especially if the air blades are machined out of a sheet metal ring and form an integral sheet metal part.
With respect to the fastening of the air blade sheet metal part(s) to the ribs of the brake disc, a very wide range of connecting techniques may be considered. For example, the air blade sheet metal parts can be connected by material bonding to the ribs and particularly, in so doing, may be integrally cast. However, it is also possible to connect the air blade sheet metal part in a shape-locking manner to one or more ribs, for example, by “clipping on” using flexible clamps. This is preferably performed with a sheet metal ring, which supports the air blades and with respect to a simple attachment to the brake disc is not closed, but rather open. That is, the sheet metal ring is configured so as to be interrupted and, hence, at least slightly flexible. Finally, it is possible to connect the air blade sheet metal part(s) in a force-locking manner to the ribs, for example, by riveting or screwing on.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.